Display screen or portion thereof with a graphical user interface



FIG. 1 is a front view of a first embodiment of a display screen or portion thereof with a graphical user interface.

FIG. 2 is a front view of a second embodiment of a display screen or portion thereof with a graphical user interface.

FIG. 3 is a front view of a third embodiment of a display screen or portion thereof with a graphical user interface.

FIG. 4 is a front view of a fourth embodiment of a display screen or portion thereof with a graphical user interface.

FIG. 5 is a front view of a fifth embodiment of a display screen or portion thereof with a graphical user interface; and,

FIG. 6 is a front view of a sixth embodiment of a display screen or portion thereof with a graphical user interface.

The broken lines showing a display screen or portion thereof, as well as portions of the graphical user interface illustrate portions of the article, and form no part of the claimed design. 

CLAIM The ornamental design for a display screen or portion thereof with a graphical user interface, as shown and described. 